Method of making bladed rotors



June 14, 1966 D. J. CLARKE METHOD OF MAKING BLADED ROTORS Original FiledSept. 8, 1961 INVENTOR.

DANIEL J. CLARKE ATTORNEYS United States Patent 3,255,515 METHOD OFMAKING BLADED ROTORS Daniel J. Clarke, Bay City, Mich., assignor to TheStalker Corporation, Essexville, Mich., a corporation of MichiganOriginal application Sept. 8, 1961, Ser. No. 136,877, now Patent No.3,173,655, dated Mar. 16, 1965. Divided and this application Jan. 25,1965 Ser. No. 433,246

2 Claims. (Cl. 29156.8)

This application is a division of copending application Serial No.136,877, filed September 8, 1961, now Patent No. 3,173,655, issued March16, 1965, and the invention relates to bladed rotors for use incompressors, turbines and the like, and to a method of making the same.

The customary designs and procedures for making a multi-stage bladedrotor includes diflicult problems concerning the locating and theassembling of the parts. Where a unitary or integral ,drum is employedwith the blades extending therethrough, there arises a difficult problemof holding the various parts in their proper relation during the brazingoperation in a furnace. This requires elaborate fixturing and furthermay result in the necessity of scrapping the whole multi-stage rotor ifsome of the blades or parts fail to be brazed.

The apparatus and method of this invention eliminates these diflicultiesby the provision of a plurality of annularly formed cups each of whichform individual internesting stages which make up a complete rotor. Eachstage of this rotor includes self-aligning and self-supportingcomponents and eliminates the need for elaborate fixturing. Each stagemay be individually brazed by fused metal and individually inspected toassure the proper bonding of the parts.

The cups are formed of sheet metal and each has an outer peripheralportion with a joggle formed therein providing for the interfitting ornesting of the stage including'the cup with adjacent stages. The stagesmay then be assembled and fused together as a unit in a furnac e. Theresulting multi-stage motor of this invention is characterized by alowpolar moment of inertia, light weight, and economy of fabrication. Thelight weight and low polar moment of inertia are in part achieved by thesheet metal fabrication which provides for thinner walls than can bemachined economically.

An important object of this invention is the provision of a lightweightrotor as outlined above with a relatively small polar moment of inertia,and a method of making the same.

Another object of this invention is to provide a composite rotor theparts of which are self-positioning and self-supporting for a furnacewelding operation.

A further object of this invention is to provide a multistage sheetmetal rotor consisting of a plurality of internesting parts each ofwhich parts constitute an individual 7 stage of the rotor.

Other objects and advantages of the invention will be apparent from thefolowing description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a fragmentary axial section through a multistage rotorconstructed according to this invention;

FIG. 2 is a fragmentary vertical section taken generally along the line2-2 of FIG. 1;

FIG. 3 is a fragmentary elevational view of one of the stages of therotor of FIG. 1 showing the blade holes or slots with the bladesremoved;

FIG. 4 is an enlarged fragmentary detail of a portion of FIG. 1 showingthe attachment of one'of the blades and the internesting of the cups;and

FIG. 5 is a section through one of the blades taken generally along theline 5-5 of FIG. 4

Fee

Referring to the drawings, which illustrate a preferred embodiment ofthe invention, a rotor 10 comprises aplurality of sheet metal cups12-17. Each of the cups is formed with a generally axially, rearwardlyextending rim portion 18, and an integral generally radially extendingwall 19. Each cup 12-17 has a joggle such as indicated at 20 preferablyformed at the forward or smaller V diameter of the rim portion 18 sothat one cup can be received in part telescopically on or within the rimof an adjacent cup.

Each cup has peripherally spaced blade openings or slots 24 formed inits rim. For instance, the cup 13 in FIG. 3 has a plurality ofperipherally spaced blade slots 24 formed therein conforming to theblade sections,-in shape. Each blade 26 extends radially inwardlythrough a slot 24 for support by a sheet metal blade supporting disk 28,as shown in enlarged detail in FIG. 4. The blades 26 conform closely tothe adjacent surfaces of the slots 24 to provide proper brazingclearance when the blades are furnace Welded in place.

The disks 28 are formed with forwardly extending annular flanges 29which cooperate with rearwardly extending annular flanges 30 formed as apart of the walls of the cups. The adjacent edges of the flanges 29 and30 are in contiguous relation in the assembled condition of the cup anddisk.

The multi-stage rotor 10 comprises the sub-assemblies 30-35. Eachsub-assembly comprises a stage of blades 26, a blade supporting disk 28and a cup. For instance, the sub-assembly 31 comprises the cup 13, theblade supporting disk 28, and the blades 26 which extend radiallythrough the slots 24 in the rim portion 18 of the cup to straddle thesupport disk to which they are jointed by fused metal, preferably byhigh temperature solder commonly known as brazing material.

The means for securing the blades in fixed assembled condition withinthe individual sub-assemblies 30-35 include legs 40 and 41 of the bladewhich straddle the disk 28. The blades are preferably located at theirinner ends by a small prong 50 formed on the leg 40 and seated in a hole52 forming a sort of detent. The projection of the prong 50 into thehole 52 is small enough so that the legs 40 and 41 of the blade 26 canbe sprung into place with the prong 50 entering the hole 52. In FIG. 2,it may be seen that the disk 28. is formed with a plurality of angularlyspaced openings 52 within which the blades 26 of the sub-assembly areassembled and held.

Each of the sub-assemblies 30-35 for a rotor 10 is assembled and brazedseparately. This makes possible the complete examination and inspectionof each subassembly independently of the others. If one sub-assemblyproves faulty it can be discarded. If the rotor structure were made ofan integral drum extending across all the stages, a defective .part orjoint could cause the scrapping of the whole rotor. With the individualsubassemblies the possible scrapping is limited to the defectivesub-assembly only.

Another feature of the invention is the relative axial location of theparts without resorting to expensive jigging.

To this purpose, the flanges 29 and 30 are extended to bear on oneanother. After the sub-assembly is brazed the flanges are cut away asindicated by the dotted portions the indirect method of this inventionthe drum is assembled from separate cups brazed together. At firstexamination this appears to be more expensive and heavier, but furtherstudy shows that the advantages of self-location greatly outweigh any ofthe integral drum which would require elaborate fixturing to hold theparts in proper relation during the brazing operation in a furnace. Infact such fixturing would have to be reconditioned after each passthrough the furnace. This would entail a prohibitive cost.

Furthermore, by using a cup construction one of the disks is integralwith the cup (or drum) and requires no fixturing for location orbrazing. This integral construction is the lightest in Weight.

The assembled rotor 10 may then be suitably secured to a shaft, asindicated in FIG. 1 wherein the shaft 60 is formed with an annular fronthub 61 have a lip portion 62 proportioned to engage the joggle of thecup 12. The forward wall 19 of the cup 12 may be removed by cutting oreliminated, as desired, for this purpose.

The back hub 65 of the shaft 60 may be secured to the rotor 10 by meansof an annular ring 66 secured to the outer surface of the adjacent disk28 immediately below the legs of the blades. The hub 65 may be flangedas indicated at 67 to receive a plurality of bolts 68 which extends intothe ring 66. Also, an annular closure plate 70 may also be retained bythe flanges 66 and the bolts therethrough to cooperate with a dependingring 71 carried on the assembly 35.

It is therefore seen that this invention provides a rotor drum structurewhich is made up of a plurality of subassemblies consisting ofindividual cups and disks for retaining the blades. The rotor structure,in itself, provides in large part of the self-positioning of the bladesand other parts, which is important to achieve low cost particularlyduring the brazing operation. The assembled rotor is characterized by alow polar moment of inertia by the utilization of sheet metal whichresults in thinner walls than can be machined economically.

While the form of apparatus and the method herein described constitutesa preferred embodiment of the invention, it is to be understood that theinvention is not limited to this precise form of apparatus and method,and that changes may be made therein without departing from the scope ofthe invention which is defined in the appended claims.

What is claimed is:

1. The process of forming a multi-stage bladed rotor comprising thesteps of forming a plurality of individual sub-assemblies representingseparate stages each including a blade-positioning annular cup formedwith a joggle in the outer periphery thereof for axial internesting withadjacent cups to form a drum, fitting a blade supporting disk withineach said cup and spacing said cup and disk from each other withintegral flanges on their radially inner edges, attaching blades to saiddisk which blades radially extend outwardly from the outer periphery ofsaid annular cup to form the sub-assembly, separately brazing eachsub-assembly making up a rotor, cutting away a portion of said integralflanges to provide access for inspection between the cup and the disks,assembling a plurality of said sub-assemblies after individualinspection into said internesting relation to form a drum, and furnacebrazing the assembled drum to form a complete multi-stage rotor.

2. The process of forming a multi-stage bladed rotor comprising thesteps of forming a plurality of individual sub-assemblies representingseparate stages by pressing sheet metal material to formblade-positioning sheet metal annularcups formed with a joggle in theouter periphery thereof for axially internesting with adjacent cupssimilarly formed to form a sheet metal drum, fitting a blade supportingdisk within each said cup and spacing said cup and disk from each otherwith integral flanges on their radially inner edges, attaching blades tosaid disk, which blades radially extend outwardly from the outerperiphery of said annular cup to form the sub-assembly, separatelybrazing each sub-assembly making up a rotor, cutting away a portion ofsaid integral flanges to provide access for inspection between the cupand the disks, assembling a plurality of said sub-assemblies afterindividual inspection into said internesting relation to form a drum,and furnace brazing the assembled drum to form a complete multi-stagerotor.

References Cited by the Examiner UNITED STATES PATENTS 2,692,563 10/1954 Kovacs.

2,825,124 3/1958 Nichols et al 29-156.8 2,850,229 9/ 1958 Stalker.2,867,407 1/ 1959 Stalker.

2,892,583 6/1959 Clarke 29156.8 X 2,925,248 2/ 1960 Stalker 253-392,937,847 5/1960 Stalker 253-39 WHITMORE A. WILTZ, Primary Examiner.

J. C. HOLMAN, P. M. COHEN, Assistant Examiners.

1. THE PROCESS OF FORMING A MULTI-STAGE BLADED ROTOR COMPRISING THE STEPS OF FORMING A PLURALITY OF INDIVIDUAL SUB-ASSEMBLIES REPRESENTING SEPARATE STAGES EACH INCLUDING A BLADE-POSITIONING ANNULAR CUP FORMED WITH A JOGGLE IN THE OUTER PERIPHERY THEREOF FOR AXIAL INTERNESTING WITH ADJACENT CUPS TO FORM A DRUM, FITTING A BLADE SUPPORTING DISK WITHIN EACH SAID CUP AND SPACING SAID CUP AND DISK FROM EACH OTHER WITH INTEGRAL FLANGES ON THEIR RADIALLY INNER EDGES, ATTACHING BLADES TO SAID DISK WHICH BLADES RADIALLY EXTEND OUTWARDLY FROM THE OUTER PERIPHERY OF SAID ANNULAR CUP TO FORM THE SUB-ASSEMBLY, SEPARATELY BRAZING EACH SUB-ASSEMBLY MAKING UP A ROTOR, CUTTING AWAY A PORTION OF SAID INTEGRAL FLANGES TO PROVIDE ACCESS FOR INSPECTION BETWEEN THE CUP AND THE DISKS, ASSEMBLING A PLURALITY OF SAID SUB-ASSEMBLIES AFTER INDIVIDUAL INSPECTION INTO SAID INTERNESTING RELATION TO FORM A DRUM, AND FURNACE BRAZING THE ASSEMBLED DRUM TO FORM A COMPLETE MULTI-STAGE ROTOR. 